More celebs are schlepping in and out of Brooklyn than around Park Avenue, Fifth Avenue or Madison. Greenpoint’s once semi-tacky manufacturing warehouse now encompasses the glorious bones and fabulous moustache of Tom Selleck.

Upon entering this studio, where Julianna Margulies also shoots “The Good Wife,” is an arrow. Its sign reads “Bathroom.” Another sign: “Toss all food items in outside trash.” Lining the wall a dozen “call sheet” envelopes that say “Crew List,” “One-liners,” etc.

Two p.m., in jeans, sneaks, shades hooked onto his shirt, Donnie Wahlberg, playing Detective First Grade Danny Reagan, Selleck’s son, announced: “I’m outta here. I had a 7 a.m. call time. Although I’m from Boston and used to the cold, I’m going home.”

In a cubicle near “Wardrobe” — a room with racks of blue cop uniforms and yellow security jackets — gorgeous Tom Selleck, changed from his sweater to a blue suit, white shirt, proper tie, spit-shined black shoes for a scene visiting the mayor, told me: “We were honored to be the first show to shoot at the World Trade Center. We shot 7 p.m. to 10:30, around the waterfall, with dimmed lights. It was overwhelming. Spiritual. So many thoughts in your head. You had to work with your thoughts.”

About “Blue Bloods” slotted on Fridays 10 p.m., he said: “I had questions about it, but ratings-wise executives keep score and we’ve won every Friday night. When I started ‘Magnum,’ Thursday was supposedly a dead night but that changed. Each show finds its way.

“I’ve been offered lots of series, but they didn’t interest me. This attracted me and because New York City is a character in it. I’m a reactive actor and plenty’s here to react to.”

MEANWHILE, on the political pages, will somebody suggest John Liu should maybe hang it up? . . . And on the sports pages, before NFL commish Roger Goodell’s headlines over footballers accepting bounties, where was he the night before? Surrounded by mayoral hopeful Scott Stringer and Paramount boss Brad Grey inhaling corned beef on rye plus potato salad at Katz’s Deli.

BEFORE Manhattan Supreme Court jury duty, Joanne Binder watched a prospective jurors’ informational video. It featured Ed Bradley of “60 Minutes.” Bradley died in 2006 . . . Michelle Williams, Independent Spirit winner for her Marilyn movie: “I was nominated four times before and never won. I was like the Susan Lucci of awards.”

A JULIANNE Moore quote: “I had concern about nudity when Robert Altman wanted me to take my top off. When he said he wanted me to be bottomless, I said, ‘You kidding? I’m a serious actress. Of course I’ll take my pants off. That’s dedication.’ In any locker-room I’m reminded we all look exactly alike. The jewel in my crown was ‘Boogie Nights,’ where I performed naked porn.”

Julianne can be seen in HBO’s “Game Change” this week where, fully clothed, she plays Sarah Palin.

NEW Yorker Ellen Easton has written Sen. Orrin Hatch before whom Mickey Rooney testified last year on elder abuse: “You proudly had your photograph taken, recognizing my friend was not only one of America’s great talents but a WWII Bronze Star vet who served his country with honor . . . Mickey doesn’t need more photo ops, he needs help resolving his egregious legal matter.”

Something “must be done to relieve him from whatever years he has left, living in fear of financial ruin.”

He and ailing wife, Jan, are spending whatever they had for their future on lawyers. Plus “costs accrued for a conservator appointed to preserve their financial assets.”